Dynamo-electric machine and system of control.



R. LUNDBLL. DYNAMO ELECTRIC MACHINE AND SYSTEM OF CONTROL. APPLICATION FILED NOV. 28, 1913.

1 1 17,372. Patented Nov. 1?, 1914.

E3 wva wtoz wzzrgrwm nished by to increase the chi UNITED STATES PATENT ()FFICE.

ROBERT LUNDELL, or new YORK, N. Y.

DYNAMO-ELECTRIC MACHINE AND SYSTEM OF CONTROL To all whom it may concern:

Be it known that I, ROBERT LUNDELL, a the United States, and a resident of'New York, borough of Manhattan, county and State of New York, have made a new and useful Invention in Dynamo-Electric achines and Systems of Control, of which the following is a specification.

he present invention relates to improvements in that class of motors and dynamos in which the main field excitation is fur an independent or auxiliary source of E. M. -F., and it relates in particular to'improvements in the said auxiliary source of excitation.

e objects of the invention are z-first ciency of the said auxil iary source of E. M. particularly at its maximum load or duty. Second, to resize, weight, cost, wear and tear of the said auxiliary 'source of E. M. F. to a- Third, to efiectimprovements in regard to reliability, simplicity'and'flexibility of a system of control which comprises a line circuit, a main motor or generator, a re versing switch, a speed adjusting controller ant an auxiliary source of field excitation for the said main motor or dynamo.

' n my previous U. i Patents No. 654,551 of July 24, 1900 No. 857,184 of June 1907 I have shown and described an auxiliary source of variable E. M. F consisting of a comparatively small motor-generator set, in which the motor-armature isconnected to the line circuit and the generator-armature to the excitation windings of the main motor, both armatures being me. chanically connected together. This unit practically constant was designed speed, no matter if the excitation current furnished by the generator-armature was to e large or smalh n the present invention the motor-generator is at a variable speed, the maximum a minimum speed when duty is called for. That is to say, the motor-generator runs at its highest speedwhen the main machine (motor or dynamo) runs at its lowest speed and vice The full load losses of the motorgenerator are furthermore substantially reecause only one armature core and only one field magnet are required for this unit, as will hereinafter be. fully described. 'e'ferring now to t e accompanying draw- \N Specification of Letters Patent.

Application filed November 28, 1913.

Patented Nov. 1?, 1914. Serial No. 803,486.

ing, which is diagrammatic, M represents a main motor or dynamo of the compensated type which I have previously fully described in U. S. Patent No. 857,184 above referred to, A and F representing respectively the distributed armatureand fieldwindings of the machine.

G represents an source of E. M. h. and it consists generator unit which the armature windings of the motor and the generator are both wound upon the same necessity fora second field unit is consequently .tary voltage transf represents nected in series high potential magnet. This reduced to a simple ro ormer. a series field winding conwith the motor end (2'. e. the side) of the unit. The low voltage generator side of. the motor-genen ator is y means 0 areversing switch E connected to' the excitation leads 12 and 13 of said leads being located at 90 electrical de rees to the line of magnetization of the armature. as clearly shown on the drawing.

14, 15 and 16 indicate other leads or terminal points for connecting the distributed eld winding of the main machine in series with its armature.

' represents starting resistances which, when not short-circuited. are in series with the armature winding of the main machine.

represents a group of other relatively igh resistances which are connected in se ries with the motor side of the motor-generator and which are arranged to become more or less short-circuited by'a speed regulating controller C as shown on the drawing. These resistances serve the purpose of regulating the speed of the said motor-generator substantially in the same manner as the speed and the output of an ordinary series motor, which for example may be driving a an, are regulated by similarexternal resistances.

Referring again to the leads or terminal points lit. 15

line current, it is not to employ necessary core, avoiding, thereby, the

Q1 run up to its maximum speed and the low the controller speed. Because of four separate leads or terminal points in a reversible machine, as shown and describe in my previous Patent No. 857.184 above referred to.

The effect of the three point arrangementillustrated in the present diagram is approximately equivalent to an arrangement of four leads wl'iich are symmetrically placed with reference to one another and to the armature-field at an angle equal to one hall of the angle shown between the leads 1% and 16 in the present diagram. in other words, the leads H and '15 are approxin'iatel equivalent to another pair of leads which would he placed exactly electrical degrees apart and at an angle to the line 0 armatureoi'iagnetization equal to one-half oi the an e between the said lead 1- and the said lure of armature-magnetization.

The present. arrangement has the advantage of greater simplicity and makes it possible to connect the armatureand the conipensatingwindings pcrinanentlj together as a sins; unit in a reversible machine.

' 25 The direction of rotation of the main machine is in the present invention re erse iiv reversing the independent excitation obine from the auxiliary source of E.- M. and by shifting the main current termil from point 14 to 16. In other words current through the armatureand the compensatingwindings is not reversed, ch in turn efiect-s a distanct advantage high potential system) in that the i Q winding may always remain negative or the ground side. .a wing now called attention to the most unit elements of my present inventhe operation of the combined appa- 5 may best be described as follows posing that the reversing switch E is (1 the controller C is first moved into position indicated by the dotted line 1. motongenerator is thereby caused to all of the external resistances R are short-circuited. The armature winding on the motor side (it the motor'generator is now receiving its maximum E. M. F. from the line circuit voltage generator side of the said motor-generator will consequentlv drvelop its maximum E. M. F. andcurrcnt tor the maximum independent excitation of the main machine M. In position 2 of the con- 55 troller the main machine M has been started as a motor because the main line current is then flowing through the starting resistances P, the armature and the compeir s'ating winding point. At position. for all of the starting resistances have become short-circuitcd and the main machine M is now operating directly across the line with its maximum independent field excitation and at its lowest fixed the angular displace nn'asre ment of the terminal 14 there is a slight field'excitation produced by the main line current which is added to the independent excitation when tl machine operates as a motor and which is subtracted therefrom when the machine is driven as a dynamo. In other words, the l ma chine nas a pound characteristic when working as a motor and a ditl'crential ClliilC'ilEi'iStlG' when working as a dynamo. in order to reverse these two characteristics it is only necessary to rci erse the relative positions 0 the two left hand movable contacts oi? the reversing switch it. l urtherinore should a plain shunt characteristic be desired such a characteristic is readily ohtainedhv closing the switch ll which arranged to short-circuit the two terminal. points is and In the fell wing positions of the controller C, via, 5 to 10 inclusive. the speed and the output oi the motor-generater (l have gradually been reduced to a small rclr we value. The independent excitation of: the main machine M has-consequently been cor respondinglv reduced and the speed increased. Assuming that the switch H is open the compounding of the main machine M (running as a motor delivering a con stant torque) has been gradually increased from a very small percentage of compound ing at position l, when the armature current is small, to very high percentage of compounding at position 10, when the armature current is la That is to say, the indcpi dent excitation is in position 10 of a ver; small value as compared with the excitation which is ol tained directly from the line current. in position ll the motor side of the motor-generator is even disconnected from the line. circuit and the speed i the same as well as the value of the independent excitation turnishcd by this source has become 0. The main machine is now running at a very high speed as a series motor having weal: field excitation. it will he understood that. it the switch H were closed. the independent field excitation would he the only field excitation for the main machine M and the controller C could in this case not be moved into its extreme 'POSltlOilS. l0 and El. it will also be understood that the motor-generator will run at a certain fixed speed (whatever it happens to be, at any one position of the controller though it is being driven as a plain series motor.

The series ield winding generator solves the problem of providing eflicient field excitation for the motor-generator at heavy loads and it avoids the diiiiculty with a shunt winding which has to be desigh'ed for a hi gh potential machine of comparatively small size or proportions Having thus described my invention what "coirof the motor- I claim and desire to secure by Letters Patent of the United States is- 1. The combination of a series wound motor-generator and a main dynamo electric machine having its excitation field winding connected to the generator side of the said motorgenerator; together with means for varying the speed and the output of the said motor-generator.

2. The combination of a power circuit, a main dynamo electric machine, a motor-generator provided with a high voltage motor winding and a low voltage generator winding upon the same armature core, said high voltage mot-or winding being operatively connected to the said power circuit and the said low voltage generator winding being connected to the excitation field winding of the said main dynamo electric machine; together with means for varying the output of the said motor-generator.

3. The combination of a main motor or dynamo and a power circuit therefor, a motor-generator operatively connected to the said power circuit with its motor armature in series with its excitation field windin the generator armature of the said motor generator being connected to the excitation field winding of the said main motor or dynamo, with means for varying the speed and the output of the said motor-generator.

at. The combination of a power circuit, a main motor or dynamo having a single distributed field winding for excitation and for compensation, with a motor-generator operatively connected to the said power circuit with its motor armature in series with its excitation field winding and having .its generator armature connected to the distributed field winding of the said main motor or dynamo.

The combination of a power circuit, a main dynamo electric machine having a single distributed field winding for excitation and for compensation, a motor-generator provided with a. high voltage motor windmg and a low voltage generator winding \upon the same armature core, said high voltage'moto-r winding being operatively con..- nected to the said power'circuit and the said low voltage generator winding being con nected to the distributed field winding of the said dynamo electric machine; to ether with means for varying the compounding of the excitation of the said main dynamo electric machine.

6. A power circuit, a main motor or dynamo having a single distributed field winding for excitation and for compensation; in combination with a series wound motor-gen- Wit! or patent may be obtained for in cents each,

- tor or dynamo of the erator operatively connected to the said power circuit and adapted to furnish a separ'ate or independent current for the excitation of the said main motor or dynamo, and means for varying the compounding of the excitation of the said main motor or dynamo.

7. i. power circuit, areversible main mo-' tor'or dynamo of thecommutator type,'a distributed field winding for the said main motor or dynamo having one of its field terminals connected to one of the armature terminals; in combination with two other field terminals, each located at less than 180 electrical degrees from the first mentioned terminal. and means .for connecting one or the other of the said two field terminals to the said power circuit.

8. A power circuit. a reversible main motor or dynamo of the commutator type, a distributed field winding for the said main motor or dynamo having one of its field terminals connected to one of the armature terminals; in combination with an auxiliary source of E. M. F. supplying a separate or independent current for the excitation of the said main motor or dynamo, and means for reversing the direction of the excitation current obtained from the said auxiliary source of E. M. F.

i). A power circuit. a separately or independently excited main motor or dynamo oi the commutator type, a distributed field I winding for the said main motor or dynamo having one of its main field terminals connected to one of combination with two other main field terminals provided with means for connecting one or the other of the said two field terminals to the said power circuit, and additional means for closing a short-circuit between the said two field terminals.

10. A power circuit. a reversible main mocommutator type havmg a distributed field winding which is connected together with the armature as one unit; in combination with an auxiliary source of E. M. F. adapted to supply a separate or independent excitation current for the said main motor or dynamo and means for reversing thedirection of the said independent excitation current and additional means for varying the compounding-of the excitation of the said main motor or dynamo. In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ROBERT LUNDELL. Witnesses:

C. J. KINTNER, M. F. Kna'rmo.

the armature terminals; in 

